/**
 * v-dialogDrag 弹窗拖拽
 * Copyright (c) 2019 ruoyi
 */

export default {
	bind(el, binding, vnode, oldVnode) {
		const value = binding.value;
		if (value == false) return;
		// 获取拖拽内容头部
		const dialogHeaderEl = el.querySelector('.el-dialog__header');
		const dragDom = el.querySelector('.el-dialog');
		dialogHeaderEl.style.cursor = 'move';
		// 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
		const sty = dragDom.currentStyle || window.getComputedStyle(dragDom, null);
		dragDom.style.position = 'absolute';
		dragDom.style.marginTop = 0;
		let width = dragDom.style.width;
		if (width.includes('%')) {
			width = +document.body.clientWidth * (+width.replace(/\%/g, '') / 100);
		} else {
			width = +width.replace(/\px/g, '');
		}
		dragDom.style.left = `${(document.body.clientWidth - width) / 2}px`;
		// 鼠标按下事件
		dialogHeaderEl.onmousedown = (e) => {
			// 鼠标按下，计算当前元素距离可视区的距离 (鼠标点击位置距离可视窗口的距离)
			const disX = e.clientX - dialogHeaderEl.offsetLeft;
			const disY = e.clientY - dialogHeaderEl.offsetTop;

			// 获取到的值带px 正则匹配替换
			let styL, styT;

			// 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px
			if (sty.left.includes('%')) {
				styL = +document.body.clientWidth * (+sty.left.replace(/\%/g, '') / 100);
				styT = +document.body.clientHeight * (+sty.top.replace(/\%/g, '') / 100);
			} else {
				styL = +sty.left.replace(/\px/g, '');
				styT = +sty.top.replace(/\px/g, '');
			}

			// 鼠标拖拽事件
			document.onmousemove = function (e) {
				// 通过事件委托，计算移动的距离 （开始拖拽至结束拖拽的距离）
				const l = e.clientX - disX;
				const t = e.clientY - disY;

				let finallyL = l + styL;
				let finallyT = t + styT;

				// 移动当前元素
				dragDom.style.left = `${finallyL}px`;
				dragDom.style.top = `${finallyT}px`;
			};

			document.onmouseup = function (e) {
				document.onmousemove = null;
				document.onmouseup = null;
			};
		};
	},
};
